Plait-forming mechanism for sewing machines



Jan. 22, 1935- H. CORRALL ET AL PLAIT FORMING MECHANISM FOR SEWING MACHINES Filed April 'r, 1952 3 Sheets-Sheet 1 Wmmmmm gnumm AI eJ-beJ-Z CarraZZ and James Hegyze attozmy/ Jan. 22, 1935. H. CORRALL ET AL 1,989,051

PLAIT FORMING MECHANISM FOR SEWING MACHINES Filed April 7, 1952 s Sheets-Shet 2 gwoe/ntoza Herberf Corral] and Jam as Hcyyz'e Jan. 22, 1935.

H. CORRALL ET AL PLAIT FORMING MECHANISM FOR SEWING MACHINES Filed April 7, 1932 1 I m nm myur mmllm 6' 5 Sheets-Sheet 3 flwmboqa Herberf cal-rail and James 11w? Patented Jan. 22, 1935 UNITEDSTATES PLAIT-FORMIN G MECHANISM FOR SEWING MACHINES Herbert Corrall, Helensburgh, and James Heggie,

Clydebank, Scotland, assignors to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application April '2, 1932, Serial nmsoavsc In Great Britain April 1, 1931 -6 Claims.

This invention relates to improvements in plait-forming mechanism for sewing machines for use in plaiting hat linings, the backs of shirts, and like articles.

Plait-forming mechanism according to the invention comprises a plait-forming blade engageable with the upper side of the work under the action of a spring and adapted to be reciprocated in the line of. feed in advance of the stitching point, said blade being pivotally supported from the lower end of an arm secured to a rock shaft adapted to bevrocked toactuate said blade by a rotary cam and being tilted clear of the work in its return stroke under the control of cam means rotating with the first mentioned cam.

To control the depth of plait while the sewing machine is in operation,'there is secured to the rock shaft a lever presenting a slot in which is adjustable a slide block operated by thefirst cam to rock the slotted lever, the arrangement being such that by shift of the slide block in the slot the travel of the plait-forming blade may be varied to any desired extent between its minimum and its maximum throw. Pivotally mounted on the slide block is a second slide block engaging a slot presented by 'onearm of a two-armed lever whose other arm carries a follower co-operating with. the first cam. 'In the minimum throw or zero position of the plait-forming mechanism the slide blocks are substantially in alignment with the fulcrum of the two-armed lever so that, when the two-armed lever is rocked, the slide blocks are substantially stationary. With movement of the slide blocks away from said fulcrum towards the rock shaft the throw of the slide blocks increases and increased travel is imparted to the plaitforming blade.

The plait-forming member is constituted as a blade spring overhanging the throat plate and presenting a work-engaging edge which is notched to embrace the needle at the end of the forward travel of said member.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a rear elevation and Fig. 2 a fragmentary front elevation of a sewing machine equipped with the improved plait-forming mechanism; Figs. 3 and 4 are end elevations at 180 to one another, drawn to a larger scale; Figs. 5 and 6 are plan views; Figs. '7 and 8 are detail views of the bracket member which carries the plait-forming blade.

Referring to the drawings, 1 denotes a plaitforming blade engageable with the upper side of the work under the action of a spring 2 and adapted to be reciprocated in the line of feed in advance 'of'the stitching point. The blade 1 is pivotally supported from the lower end of an arm 3 securedto a rock shaft 4 adapted to be rocked to actuate the blade by a cam 5 mounted on a rotary shaft 6 driven through gears 6', 6 from an intermediate shaft 6 connected by a belt 6 with the main shaft '7 of the machine, the blade being tilted clear of the workin its return stroke under thecontrol of means including cams 8, 9 carried by the gear 6, all as will be hereinafter described in greater detail.

-To control the depths of plait while the sewing machine is in operation, there is secured to the rock shaft 4 a lever 10 presenting a slot 11 in which is adjustable a slide block 12 operated by the cam 5 to rock the lever 10, the arrangement being such that by. shift of the slide block 12 in the slot. 11 the travel of the blade 1 may be varied to any desiredextent betweenits minimum and its maximum throw.

Unitary with the slide block 12 is a'pivot 13 (Fig. 5) on which is mounted a second slide block 14 movable in a slot 15 presented by one arm 16 of a two-armed lever 16, 16' fulcrumed between its ends at 1'7 and carrying on its arm 16' a follower 18 cooperating with the cam 5. In the minimum throw or zero position of the plaitforming mechanism the slide block pivot 13 is substantially coaxial with the lever fulcrum 1'7 so that, when the lever 16, 16 is rocked by the cam 5, no rocking movement is imparted. to the lever 10. With movement of the slide blocks 12, 14 away from the fulcrum 17 towards the shaft 4 the throw of the lever 10 increases and increased travel is imparted to the plait-forming blade.

Adjustment of the slide blocks 12, 14 lengthwise of the slots 11, 15 is permitted by slackening a wing nut 19 engaging a screw-threaded stem 12 integral with the slide block 12 and serving when tightened, to lock the slide block 12 to the lever 10. 20 denotes an index member carried by the slide blocks and cooperating, to indicate the setting of the plait-forming mechanism, with a scale (not shown) calibrated on the upper surface of the lever 16.

The blade 1 is carried by a bracket 21, Figs. 6, '7 and 8, pivotally mounted on and turnable relative to a pin 22 journalled in the lower end of the arm 3 and having an overhung end on which is secured an arm 23 to whose free end is pivotally connected at 24 the lower end of a link 25 whose upper end is pivotally connected at 26 to one arm 27 of a two-armed lever 27, 28 fulcrumed at 29 and presenting on the arm 28 a follower 30 cooperating with the cams 8, 9.

In the forward or operative stroke of the plaitforming mechanism the blade 1 is pressed downwardly into engagement with the work by the action of the spring 2 on a finger 31 unitary with the bracket 21; the follower 30 being engaged by one of the cams 8, 9 whereby to maintain the arm 23 in depressed position in opposition to the action of a tension spring 25' acting on the link 25. In the return stroke of the plait-forming mechanism both cams 8, 9 are clear of the follower 30 so that the arm 23, but not the blade 1, is raised by the action of the spring 25', whereby a member 32 carried by the arm 23 engages the spring 2 and raises it clear of the finger 31 tilt the blade upwardly clear of the workin its return stroke. The member 32 is adjustable angularly with respect'to the arm 23, being unitary with a plate 32' presenting an arcuate slot 34 penetrated by a bolt 35 which also penetrates the arm 23.

The blade 1 overhangs the throat plate 36 and is provided on its work-engaging edge with a" notch 37 for penetration by the needle 38 carried by the vertically reciprocating needle bar 39.

40, 41 denote the presser bar and the presser foot, respectively.

What is claimed is:--

1. Plait-forming mechanism for sewing machines, comprising, in combination, a reciprocatory plait-forming blade, a rock-shaft, an arm on said shaft pivotally supporting said blade, a rotary cam for effecting rocking movements of said shaft to reciprocate said blade, and means including a cam rotating with said first mentioned cam causing said blade to engage the work in its forward stroke and to move clear of th work in its return stroke. 2

2. Plait-forming mechanism for sewing ma-I chines, comprising, in combination, a recipro-' catory plait-forming blade, a rock shaft, an arm on said shaft pivotally supporting said blade, a rotary cam for effecting rocking movements of said shaft to reciprocate said blade, a spring reciprocating with and urging said blade towards the work, and cam controlled means for moving said blade clear of the work on its return stroke.

3. Plait-forming mechanism for sewing machines comprising, in combination, a reciprocatory plait-forming blade, a rock-shaft, a depending arm on said shaft pivotally supporting said blade, means for effecting rocking movements of said shaft to reciprocate said blade, an arm pivotally carried by said depending arm, a cam-controlled lever and depending link for rocking said last-mentioned arm, and means controlled by the rocking movements of said arm for causing said blade to, engage the work in its plaitforming stroke and for lifting it clear of the work in its return stroke.

4; Plait-forming mechanism for sewing machines comprising, in combination, a reciprocatory plait-forming blade, a rock-shaft, a depending arm on said rock-shaft pivotally supporting said blade, means for effecting rocking movements of said shaft to reciprocate said blade, a spring reciprocating with and urging said blade toward the work in the plait-forming'stroke of porting said blade, means for effecting rockingmovements of said shaftto reciprocate said blade,

a cam-controlled lever, a swinging link depending from said lever, and means connected to the lower end of said link and'to sai'd'blade'for causing said blade to engage the work in its pl'ait-formin'g stroke and to move clear of the work in its return stroke.

6. In a plait-forming mechanism, a rocker. arm, a reciprocatory plait-forming bladepivotally carried by said arm, a spring carried by said arm and reciprocating with and urging said blade about its pivot toward the work in the plait-forming stroke, and means for relieving said blade from the urge of said spring: in the return stroke of said blade:

HERBERT 'CORRALL.

JAMES HEGGlE. 

